Flexible package-forming machine for horizontal packaging and method of manufacturing flexible packages

Abstract

The present invention relates to a flexible package-forming machine for horizontal packaging and method of manufacturing flexible packages. The proposed forming machine consists of an unwinding unit (11), a perforating unit (12), a folding unit (14), a welding unit (16), and a cutting unit (17), wherein a compensating unit (13) is further included intercalated between the perforating unit (12) and the folding unit (14), linking a section with intermittent forward movement (S1) of the flexible band (1) where the flexible band moves in an intermittent manner and including the perforating unit, and a section with continuous forward movement (S2) where the flexible band moves in a continuous manner and including the folding unit, flexible band being accumulated in said compensating unit during the forward movement of the section with intermittent forward movement (S1) and the accumulation being reduced during breaks in the forward movement of the section with intermittent forward movement.

The invention claimed is: 
     
       1. A flexible package-forming machine for horizontal packaging by folding and welding flexible band comprising, in this order with respect to a forward movement direction of the flexible band, at least:
 one unwinding unit for unwinding the flexible band in the forward movement direction; 
 one perforating unit of the flexible band for perforating the flexible band in pre-established precise positions thereof; 
 one folding unit of the flexible band configured for folding said flexible band along at least one folding line parallel to the forward movement direction, at least two portions arranged on opposite sides of said at least one folding line of one and the same face of the flexible band being arranged opposite one another; 
 one welding unit of the folded flexible band configured for making welding lines at least in a direction transverse to the forward movement direction of the flexible band; 
 one cutting unit for separating portions making up flexible packages; 
 characterized in that: 
 a movement compensating unit for compensating the movement of the flexible band intercalated between the perforating unit and the folding unit, said compensating unit linking a section with intermittent forward movement of the flexible band and a section with continuous forward movement of the flexible band, said compensating unit being provided with at least: 
 one inlet roller in contact with the flexible band with an axis of rotation perpendicular to the forward movement direction and fixed with respect to the forming machine, 
 one outlet roller in contact with the flexible band with an axis of rotation perpendicular to the forward movement direction and fixed with respect to the forming machine; 
 at least one accumulator roller in contact with the flexible band between the inlet roller and the outlet roller in the forward movement direction, and with an axis of rotation perpendicular to the forward movement direction and movable with respect to the axes of rotation of the inlet roller and the outlet roller being kept perpendicular to the forward movement direction of the flexible band; 
 said accumulator roller being provided with and/or connected to a tautening device provided for moving the accumulator roller away from the inlet roller and/or outlet roller, keeping the flexible band taut; the tautening device including: 
 springs provided for moving the at least one accumulator roller away from the inlet roller and/or outlet roller, or 
 a guiding system of the accumulator roller with a vertical component, the inlet roller, the outlet roller and the accumulator roller being horizontal rollers and the accumulator roller being at a lower height than the inlet roller and the outlet roller ( 23 ) during accumulation, causing the tautening of the flexible band by gravity; and 
 the section with intermittent forward movement includes an intermittent drive unit configured for moving the flexible band in the forward movement direction in an intermittent manner, and wherein the section with continuous forward movement includes a continuous drive unit configured for moving the flexible band in the forward movement direction in a continuous manner. 
 
     
     
       2. The machine according to  claim 1 , wherein the guiding system of the accumulator roller includes cogwheels at the ends of the accumulator roller and cogged tracks. 
     
     
       3. The machine according to  claim 1 , wherein the perforating unit is a die-cutting unit. 
     
     
       4. The machine according to  claim 3 , wherein the die-cutting unit is arranged opposite a horizontal segment of the flexible band. 
     
     
       5. The machine according to  claim 4 , wherein at least the perforating unit, the compensating unit and the folding unit are supported on a common frame defining a compact forming module, and wherein the compensating unit and the folding unit are arranged above the horizontal segment of the flexible band opposite the die-cutting unit. 
     
     
       6. The machine according to  claim 1 , wherein at least the perforating unit, the compensating unit and the folding unit are supported on a common frame defining a compact forming module. 
     
     
       7. The machine according to  claim 1 , wherein there is intercalated between the folding unit and the welding unit an additional movement compensating unit for compensating the movement of the flexible band, separating the section with continuous forward movement from an additional section with intermittent forward movement of the flexible band, said additional compensating unit being provided with at least:
 one inlet roller in contact with the folded flexible band with an axis of rotation perpendicular to the forward movement direction, 
 one outlet roller in contact with the folded flexible band with an axis of rotation perpendicular to the forward movement direction; 
 at least one accumulator roller in contact with the folded flexible band between the inlet roller and outlet roller in the forward movement direction, and with an axis of rotation perpendicular to the forward movement direction; 
 the at least one accumulator roller being movable with respect to the inlet roller and outlet roller, keeping the axis of rotation thereof perpendicular to the forward movement direction of the flexible band, and said accumulator roller being provided with and/or connected to a tautening device provided for moving the accumulator roller away from the inlet roller and/or outlet roller, keeping the flexible band taut; and wherein the additional section with intermittent forward movement includes an additional intermittent drive unit. 
 
     
     
       8. The machine according to  claim 1 , wherein the inlet roller of the compensating unit is also the intermittent drive unit of the section with intermittent forward movement of the flexible band. 
     
     
       9. A method for forming flexible packages for horizontal packaging by means of folding and welding a flexible band comprising the steps of:
 feeding a flexible band in the forward movement direction to the flexible package-forming machine by means of an unwinding unit for unwinding the flexible band; 
 driving said flexible band in the forward movement direction; 
 perforating said flexible band in pre-established precise positions by means of a perforating unit of the flexible band, obtaining a perforated flexible band; 
 folding, by means of a folding unit, said flexible band along at least one folding line parallel to the forward movement direction, at least two portions arranged on opposite sides of said at least one folding line of one and the same face of the flexible band being arranged opposite one another, obtaining a folded flexible band; 
 welding, by means of a welding unit arranged after the folding unit in the forward movement direction, the folded flexible band along at least welding lines transverse to the forward movement direction of the flexible band; 
 cutting the folded and welded flexible band for obtaining individual flexible packages; 
 characterized in that the method also includes: 
 driving with an intermittent movement said flexible band in the forward movement direction through a section with intermittent forward movement by means of an intermittent drive unit; 
 feeding in the forward movement direction and in an intermittent manner the perforated flexible band obtained from said perforating unit to a compensating unit, cyclic accumulation of the perforated flexible band taking place in said compensating unit during the movement of the flexible band in the section with intermittent forward movement; 
 driving with a continuous movement said perforated flexible band in the forward movement direction through a section with continuous forward movement after the compensating unit in the forward movement direction by means of a continuous drive unit, cyclic deaccumulation of the perforated flexible band taking place in said compensating unit during breaks in the intermittent movement of the flexible band in the section with intermittent forward movement; 
 wherein the steps of feeding the forming machine and perforating the flexible band are performed on the section with intermittent forward movement of the flexible band; and wherein the step of folding the flexible band is performed on the section with continuous forward movement of the flexible band. 
 
     
     
       10. The method according to  claim 9 , wherein after folding the flexible band produced by the folding unit, the followings is performed
 feeding in the forward movement direction and in a continuous manner the folded flexible band obtained from said folding unit to an additional compensating unit; 
 driving with an intermittent movement said folded flexible band in the forward movement direction through an additional section with intermittent forward movement after the additional compensating unit in the forward movement direction by means of an additional intermittent drive unit, cyclic accumulation of the folded flexible band taking place in said additional compensating unit during breaks in the intermittent movement of the flexible band in the section with forward movement, and cyclic deaccumulation of the folded flexible band taking place in said additional compensating unit during the movement of the flexible band in the additional section with intermittent forward movement. 
 
     
     
       11. The method according to  claim 10 , wherein the step of welding the folded flexible band by means of a welding unit are performed on the additional section with intermittent forward movement of the flexible band during breaks in the intermittent movement of the flexible band.